“I actually joined John in the studio, I guess it’s been three weeks ago,” Gibbons told hosts Mark Goodman and Alan Light. “We composed a song together and decided to lay it down. … Maybe we’ll have it wrapped up, probably in the next 24 hours.”

Gibbons revealed the song’s title: “Holy Grail.” It may or may not be the “accidental” song the pair reportedly collaborated on earlier this year. Soon after we initially posted this story, received a press release with information about it and a 30-second snippet of it. The song, which will be released digitally on June 8, was written by Fogerty and features Gibbons' boogie guitar and vocals.

“I am so happy to be playin' and singin' with the Reverend BFG," Fogerty said. "That Sharp Dressed Man, himself. This is the Holy Grail!”

The enthusiasm was mutual. “It’s not an overstatement to say that writing a song with John Fogerty is a genuine bonus!" Gibbons gushed. "It’s fair to say that John and I are both pumped about our collaboration and we think this new one called 'Holy Grail' holds true with some great storytelling and some solid guitarists movin’ the number right along. It begs a shout of, 'Turn it up!’”

Listen to a Snippet of "The Holy Grail"

Watch Billy Gibbons and John Fogerty Trade CCR and ZZ Top Riffs

Gibbons also discussed working on his next solo album, the follow-up to his debut, Perfectamundo, which was UCR’s Album of the Year for 2015. Gibbons talked about a conversation he had with his record label’s president that got the project going.

“He said, ‘Well, we’ve done that Cuban/Latino thing,’” Gibbons recalled, referring to Perfectamundo’s rhythmic influence. “'I would like to see you go back to those bluesy roots.’”

Gibbons is happy to oblige, and the result, which he’s calling Big Bad Blues, should be released in September. His band on the album consists of ex-Guns N’ Roses drummer Matt Sorum, guitarist Austin Hanks and blues harmonica player James Harman.

“This is a real stripped-down, gutbucket, raw and rough approach,” Gibbons said of working with the musicians. “It’s going to provide a nice way to present this back-to-the-blues kind of thing — Big Bad Blues.”

John Fogerty and ZZ Top’s Blues and Bayous tour kicks off tomorrow night in Atlantic City.